Internal-combustion engine



E. R. BURTNETT INTERNAL COMBUSTION ENGINE Aug. is, 1927. 1,639,165

Filed Dec. 16, 1925 2 Sheets-Sheet 1 I Z we 16 1927. Aug E. R. BURTNETT INTERNAL COMBUSTION ENGINE Filed Dec. 16. 1925 2 Sheets-Sheet 2 Nmw @ Ilumu Patented Aug. 16, 1927.

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EVERETT R.5BURTNETT, ,OFzLOSa-ANGELES, CALIFORNIA, ASSIGNOR, BY'DIRECT AND MESNE ASSIGNMENTS, TO THEVAUTOMOTIVE VALVES 00., OF-LOS ANGELES, CALL FORNIA, A1VOLUNTARY TRUST,

INTERN,ALCGMBUSTION- ENGINE.

Application filed December 16, 1925. Serial No. 75,703.

My invention relates-to an: internal combustion engine of the four stroke cycle'type and has for its principal objects the provision of a 'relatively'simple' andpractical engine unit that will produce increased power throughout the load range, to provide an en gine structure that will develop a relajtively high degree of torque at low engine speeds and also to provide a common compression and combustion'clearance chamber that joins 7 two combustion chambers and in wh1ch-common clearance chamber gaseous fuel charges are compressed andimpounded in a very compact condition with the result that: a

high degree of turbulence of the gaseous fuel charge is developed during compression and f thereby providing fora material increase in the speed of the flame propagation through the compressed charge when the latter is 1gnited.

1n the operation ofaan' internal. combustion engine, the power-developed fromcombustion beforeimechanical losses are taken from it and before power out-put after mechanical rv losses are COIlSlClGI'GCLT a primary mfiuence greater torque at ':'low engine revolution, for competitive performance .1 n: 1813131011 to steam and to obtain: this desirable: result with economy and: low-v costs off" manufacture.

Supercharginp adds tothe power developedfrom ancengine :of a; given displacement at s allengine speeds but superchargingzo means a lower compress-ion pressure at light load OP? eration as a result of the maximum com-' pression limit being; established-to the vol ume ratio OfrthG supercharge, thusfbringing about 'EL'TBCl'HCtlOII of the thermal efficiency at light iload operation;

A larger engine means increased 'costof production increased a mechanical losses,

greater heat losses bvradiation" at lightrload' operation and increasedengine weight topropel.: In: the conventionali four stroke cycleengineiwhile operating at full load and low engine speed, a condition produced when the operator :of aniautomobile is endeavoring to travelin shi'ghi gear when the. load :is very v great or the road conditions will not permit faster travel, the period of time is increased in which expansion is retarded by theslow crank pin movement to a point where piston speed is accelerated and the connecting rod angularity and crank angularity both provide leverage for piston pressure-to twist the shaft and increase piston speed. Therefore at low engine speed, the flame propagation being ust as fast as at a higher englnespeed,

the combustion 'chargeis impounded longer at maximum pressure and temperature before the pressure can be effective in power development,- owing to the dead center-positron of the piston and the lack of greater initial piston travel immediately after combustion which would permit'instantexpam sion and power development. longer duration of time-that the hot gases in which the working energy is stored in yalue 1n ratio only to'their heat are held 1n contact with the cooled walls and the loss of heat power-as a result "of 'radiation.

It lS the purpose of my invention to quicken initial BXPEIDSlOIl 1n powerdevelopment by arranging two cylinders to one common compression and'combustion chamber, said two cylinders being of different diameters, to 4 separately connect the piston: of I each cy l-" inder toa separate crankpin of the crank shaft and the crank pinof the crank shaft:

to which the smaller diameter piston is connected being disposed in the direction of crank shaft rotation in advance of thecrank pinto which the piston of largerdiameter is connected. This arrangement causes the maximum compression pressure in. the common clearance chamber to occur when the larger piston is on dead top center, at which time the smallenpiston and respective crank pin are in advance-beyond :top dead-center thereby providing. greater crank leverage at a time when maximum pressure and tempers ature is first developed. A i

in order to obtain a highrate ofcombustion, I provide in combination with the-two different displacement cylinders combustion chamber located to the side, which combustion chamber is substantially semi-spherical in form in. order to produce turbulence of 'the charge during compression. Thi common combustion chamber joins thev com-v bustion chambers of different diameters "by burn.

Hence the I the admission of gaseous fuel to the openings and the pistons are arranged ::o as to eliminate the space between their respective chambers on compression dead center with only a carbon clearance. The induction of the contents of the two cylinders at high velocity into one chamber at an uncle relative to the plane occupied by the axes of the two cylinders develops the desired degree of turbulence of the charge. The ignition device is located adjacent to the head end of the combustion chamber of least diameter so as to cause combustion to he gin in that part of the compressed vol -1e that is first to eiLpand into the piston c a placement developed by the advance initial stroke of the smaller displacement piston. Inlet and exhaust poppet vaves are pro vided in the common compression and combustion clearance chamber for controlling ie and the exhaust of products of combustion therefrom and said valves being actuated in a conventional manner for engines functioning on the four stroke cycle principle With the foregoing and other objects in view my invention consists in certain novel features of construction and arrangement of parts that will hereinafter be more fully described and claimed and illustrated in the accompanying drawings, in which Fig. 1. is a vertical section taken lengthwise through the center of an engine or my improved construction and the plane on. which said view is taken being coincident with the axes of the two cylinders and the crank shaft.

Fig. A. is a diagrammatic view illustrating the relative angular positions of the two crank throws of the crank shaft to which the two pistons of the engine power unit are connected.

Fig. 3. is a cross section taken approx matel-y on the line 3 3 of Fig. 1.

F 4. is a vertical section taken on the line 4lil of Fig. 3.

Fig. 5. is a horizontal section taken approximately on the line 55 of Fig. 1.

Referring by numerals to the accompanying drawings which illustrate a practical embodiment of my invention, des nates a cylinder block in which are formed two combustion chambers 11 and 12. the axes thereof being parallel and the diameter of chamber 11 being somewhat greater than the diameter of combustion chamber 12. if desired, two cylinders of different diameters may be arranged side by side, but as ill trated, I prefer to form the combuston chambers of differentdiameters in one cylinder block.

Gylinder block 10 surmounts a crank case 13. the latter being provided with bearings 14 for a crank shaft 15. This crank shaft has two throws. 16 and 17, the same being arranged respectively in line with the are:

1.ese,1o5

tion respectively in the co '1! 1 cha nbers 11 and 12 and'said are coir nected by conventional conn rods; such as 20 to the crank pins nits 16 and 17.

Block 10 is provided on its rear port: n

with a housing 21. in the upper portion of which are formed inlet and exhaustports 22 and 23 respectively. The inner ends of these ports terminate on the upper surface of block 10 and inner ends are provided with seats for poppet valves and 25 respectively. the conventional type and they are from their seats by cams such 26 are formed on a cam shaft 27, the latter being driven in any suit. le manner, but preferably from the crank shaft 15 at h the speed of the la ter, this being nece s in order that the valves may open an in proper time relation to the moveme the power pistons 18 and 19. lnlet port and the inlet poppet valve 2% are disposed substantially to the rear of combus chamber 12 of least diameter wh e exl port 28 and exhaust poppet located substantially to the rear 01 bustion chamber 11 of diai'neer.

Secured in any suitable manner on the head end of block 10'and its rearward extension 21 is a head block 28 in the underside of which is formed a shallow recess 29 that connects the head ends of the combustion chambers 11 and 12 and functions as common compression and combustion clearanee chamber therefor.

This common clearance chamber 29 is relatively small in area as compared to the piston sweep portions of combustion chainbers 11 and 12 and the greater portion of said chamber 29 is disposed rearwardly of the combustion chambers 11. and 12 so tha. the forward corners only of the common clearance chamber are in direct communica tion with the combustion chambers 11. and 12.

This chamber 29 also extends over the i.n ner ends of the inlet and exhaust ports 22 and 23 and provides a space for the upward or opening movements of the poppet valves 24 and 25.

That portion of the chamber 29 that is directly above the poppet valves is substantially dome-shaped with rounded ends so that when a charge of gaseous fuel is admitted to said chamber, it will tend to flow toward the center thereof.

Seated in this head 28 and preferably at a point above the combustion chamber 12 of These poppet valves are of ill) ltlU

least .diameter-zis an ignition: devicesuchias I a spark? plugrz30 and'ithe inner ends oft'ie.

electrodes thereof project'into the compressionnand combustion clearance chamber gaseous fuel charge within the clearance chamber :29 is brought about by a sparkproduced between the'inner ends, of thewelectrodes of'spark plug 30' andsuch ignitiontakes placeatrthe tiiiie -tlie-piston 18 of larger diameter passes high center, at which tllllGtllG piston-.15) of smal moved to a point awshort-d iicu pin=17 relative to crank pin 16.

As: a result'of this advanced position of thessmaller piston, .1 am able to take advantage o't theigreater cinnlcleveragei prodeveloped as a result: of the ignited fuel charge will be transmittediin the conveiitional'manner'through' connecting rods and-the: two cranks tothe crank shaft 1 and l on? the succeeding upward or inward strokesof the two plstons the products of combustion and burnt gases will exhaust through common clearance chamber :29 and through exhaust port 23,. which latterv is opened as the exhaust VitlLVB is -lifted from 5 its sseat its respective cam;

On the succeedingdownward or outward strokes-ofthe two pistons inlet valve 2 will be opened by its cam. and a charge of gaseous fuel will enter inlet port 22' and pass through chamber 29 to: the piston sweep chambers abovethe pistons Band-19.. On

the succeeding. upward or inward strokes of the two pistons thefresh' gaseous fuel charge thus drawn; into the combustion chambers will be compressed in the upper ends of said chambers and within the relatively small shallow common clearance chamber 29 and owing-to the size and contour of the latter and its location to the rearof'the chambers 11 and '12 thecharo'e of aseous fuel that is spark is produced between theinner ends of the terminals of the electrodes of spark plug 30.

Iii-this connection it will be understood that where a relatively high degree of tarbulence'of a compressed gaseous fuel charge is developed during the compression strokes of'tlie pistons the speed of the flame propagation through the compressed charge is materially increased and correspondingly the efficiency ofthe engine is increased.

29: In the. operatioirofm'y improved engine the ignition. and combustion-of a compressed diameter has nee belowtop center, due to the advanced position of crank nect Thus it'swill :bei seen: that I have provided a fourstroke cycle :internal:combustion one: Q1116: that r is relatively simple inconstruction and which inzoperation: will be highly efficient due to the variable sizes of the com.-.

bustion: chambers, theadvanced position. of one ofthe two-cranks to which the twopistons of. the power unit are connected: relative to the other crank, and the size, cone.

.tour, and location of the common clearance and 'combustion chamber which, as herein. disclosed, .is effective in imparting aihigh degree of turbulence to the compressed gaseous fuel charge.

it will be=understood-that minor changesin the size; form and construction of the various parts of my improved engine maybe to the pair of combustion cliambersso that only relatively small portionsof said common clearance chamberare in direct coirmunication with said combustion chambers, said common compression andjcombustionclearance chamber having inlet and exhaust ports, poppet valves controllingsaid ports, the axes of which poppet waives are parallel with the axes Oftl'le combustion chambers pistons arrangedfor operation within the combustion chambers-of different diameters, a. crank shaft havingtwo crank throws to whichthetwo pistons are respectively connected and the-pin of the crankthrow to wvhich the piston. Within the combustion chamber of least diameteris connected occupying an angular position in advance in the direction of crank shaft rotation from the pin of'the other crank.

2. In a four stroke 'cycle'internal combus tionengine, apair of combustion chambers of different diameters, the head ends of which combustion chambers being connected by a common compression and rombust-ion clearance chamber, the latter being offsetwith respect vto the axes of the pair of combustion chambers, and poppet vali e controlled inlet and exhaust ports arranged within said common compression andcombust-ion clearance chamber.

3. 111 a' four stroke cycle internal combustion engine, a pair of combustion chainbers ot different diameters, the head ends of which combustion chambers-being cond by a common compression and combustion cleara ce chamber, the-latterbeing int) offset with respect to the axes of the pair of combustion chambers, so that only relatively small portions of said common clear rice chamber in direct communication with the combustion chambers, said offset common compression and combustion clearance chamher being provided with poppet valve controlled inlet and exhaust ports, pistons arranged for operation within the combus tion chambers of different diameters, a crank shaft having two throws to which the two pistons are respectirely connected and the crank pin of the crank throw to which the piston within the combustion chamber of least diameter is connected occ 11g i angular position in advance in the direct) in of crank shaft rotation item the crank pin of the crank.

at. In a four stroke cycle internal conibustion engine, a pair of combustion chambers of different diameters, the head ends of which combustion chambers hei nected by a common compression ano. bustion clearance chamber, the l 1 offset with respect to the axes of the combustion chambers, so that only small portions of said common chamber are in direct communication .Ylti' the combustion chambers, poppet valve controlled inlet and exhaust ports arranged within said common compression and coinbustion clearance chamber, pistons arrr for operation within the combustion ch bers of different diameters, a crank sha' having two throws to which the pistons are respectively connected and the crank pin of the crank throw to which the piston with in the combustion chamber of least diame is connected occupying an angular position in advance in the direction of crank shaft rotation from the crank pin of the crank.

5. In a four stroke cycle internal combustion engine, a pair of combustion cylinders, the chambers within wnich are of different diameters, the head ends of said chambers being connected by a common com- 7 pression and combustion clearance Clldll'l' the latter being offset laterally from the a es of the two combustion cylinders, so that only relatively small portions of the common clearance chamber are in directcommuniczn tion with the combustion chan'ibeiti popp ralve controlled inlet and exhaust pr communicating with the rear crank lower portion of said common cc and combustion clearance chamber ar d an ignition device projecting into compression and combustion clearance riianr her at a point adjacent to the combustion chamber of greatest diameter and the poppet valve controlled inlet port.

6. In a four stroke cycle internal j0llilulli tion engine, a pair of combustion cy ders, the chambers within which are of roller-cut diameters, the head ends of the chamber id common 7 within said combustion cylinders beingconnected by a common compression and combustion clearance chamber, which latter is oi t relative to said combustion chambers so that only relatively small portions of said common clearance chamber are in direct coinmunication with said combustion cham said common compression and combusiion clearance chamber gradually increasing in depth towaro its end that is remote from the points where it is in communication with a said combustion chambers, pistons arranged ror operation within the combustion chambers of different diameters, a crank shaft l" mg two throws to which the pistons to each commonly joined pair of cylinderv chambers, the two pistons of the two commonly joined cylinder chambers being sepaceiy connected, one to each of the said two crank pins of the crank shaft, the piston stroke displacement of one of the two commonly joined cylinder chambers being less than the piston stroke displacement of the other cylinder chamber of the pair of cylinder chambers commonly oined, the crank pin to which the piston within the cylinder having the least piston stroke displacement being arranged in advace of the other of the two crank pins of the crank shaft to "which the piston within the cylinder having the greatest piston stroke displacement is connected, in advance rotatively in the direction of rotation of the crankshaft, the ratio of difference of piston stroke displacement of the two commonly joined cylinders and the ratio of spacing rot'atively in degrees between the two crank pins of the crank shaft to which the two pistons of different stroke displacement of the two commonly joined cylinders are connected, being such that the displacementof the clearance chamber common to the said two cylinder chambers will be at minimum when the piston of the greatest piston stroke displacement reaches head end dead center of its stroke and means for admitting the fresh charge and releasing the spent charge in and out of the said two cylinder common clearance chamber.

In testimony whereof I afiix my signature.

EVERETT R. BURTNETT. 

